Malicious PDF — malware analysis report

Static analysis result for SHA-256 a21961ac00470f65…

MALICIOUS

PDF

83.3 KB Created: 2021-09-18 16:01:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 374a154b57e564ff13eb5ca77ffd191b SHA-1: ba3dab3157dc48e0c76289a45cae791ed3d162f9 SHA-256: a21961ac00470f651f853bdeee52c2f4f2aba1edcf9f50b2bf092f1baf67c136
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a machine learning model and ClamAV, indicating malicious intent. The presence of numerous external URIs, many pointing to disposable hosting and configured as a link farm, suggests a phishing or malware distribution scheme. The document body is heavily obfuscated, but the heuristics indicate the primary function is to redirect users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://synerhu.ru/uplcv?utm_term=google+play+android+device+manager+ring PDF link annotation
    • http://www.startbatteries.gr/ckeditor/ckfinder/userfiles/files/rigubusopipobibajumupol.pdfIn PDF document text
    • http://huiking.cn/uploads/file/151814293172.pdfIn PDF document text
    • http://litho-and-co.fr/ckeditor/upload/files/kobepameratavevavezilenev.pdfIn PDF document text
    • https://stvorki.ru/files/file/sixarugamuvudij.pdfIn PDF document text
    • http://turnyras.lt/Files/file/zuvanutaparolewinidapu.pdfIn PDF document text
    • https://bikeid.net/ckfinder/userfiles/files/15722543357.pdfIn PDF document text
    • https://agrilaui.com/userfiles/file/87030299697.pdfIn PDF document text
    • http://confidenzacsapagy.hu/upload/terinejowabugiritewo.pdfIn PDF document text
    • https://radmangroup-ye.com/rgfiles/file/fejoxonadedul.pdfIn PDF document text
    • https://biogenetixpharma.com/ci/userfiles/files/babowodajezovobunimufuv.pdfIn PDF document text
    • http://huabulaw.com/uploadpic/2021-9/file/2021091408043773499.pdfIn PDF document text
    • http://www.gleason.com.au/application/third_party/ckfinder/userfiles/files/fuwodufotepixebefa.pdfIn PDF document text
    • http://pho32shabu.com/uploads/files/fofibifakirekiwoj.pdfIn PDF document text
    • http://www.movingintofreedom.com/wp-content/plugins/formcraft/file-upload/server/content/files/161400c61a1130---72193232868.pdfIn PDF document text
    • http://www.almansori-ye.com/almansorifiles/files/zojuliwosem.pdfIn PDF document text
    • http://opusbiz.kr/data/editor/file/486107602613ab5305f032.pdfIn PDF document text
    • https://protrialse.eu/files/files/loloxixidemifemaxowaliti.pdfIn PDF document text
    • http://strelnicebudejovice.cz/userfiles/file/1950454299.pdfIn PDF document text
    • http://auburn-companies.com/userfiles/files/29431233869.pdfIn PDF document text
    • http://okfilm.kr/userData/board/file/silife.pdfIn PDF document text
    • http://polymer-optix.de/userfiles/file/nururesemigebozaka.pdfIn PDF document text
    • http://daejonggyoyc.com/userfiles/file/20210905214909.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e263.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE263 17040 bytes
SHA-256: 099e4b7307f65456730c9da30b358c51109c7b1fad0e9bd25f9d675259a3dd2b
font_01_sfnt_off00010eb9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EB9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000126d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126D0 10808 bytes
SHA-256: 8a15ef0b17a607969200a8f4150d696893835b6d2c04d31c8f9e0e891bbe0d07

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